Verilog interview questions

I've lead only a couple of interviews but I find the best questions don't focus on VHDL/Verilog/System Verilog but instead focus on tangible logic building blocks such as gates/counters/flip-flops etc. For example a question I like to ask is the following:

How would you achieve the function of a two input XOR gate using only a multiplexer and one other logic gate (not including XOR gate!)?

Removing the constraints of the VHDL nuances means you can actually figure out if a candidate has a logical approach to problems - whether the problems are VHDL or otherwise.